Scaffolding system

ABSTRACT

A multi-level construction scaffold comprises a pair of H-shaped end frames spaced by horizontal guard rails. The guard rails are pivotally connected at opposed ends thereof to the end frame members, thereby allowing the guard rails to pivot in parallel when one of the frame member is lifted relative to the other. Each end frame includes a pair of uprights interconnected by a horizontal platform support located at a distance below the guard rails engaged with the end frames. In this way, the safety guard rails of a next level to be erected can be installed directly from the underlying level.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to scaffolding of the type used inthe construction of buildings and, more particularly, to scaffoldingassemblies wherein safety guards of an upper floor level can beinstalled from an underlying floor level.

[0003] 2. Description of the Prior Art

[0004] Temporary scaffolds are often erected alongside of buildings toenable work to be done on the building's exterior. Such constructionscaffolds typically comprise a pair of inverted U-shaped lower trussesfor supporting a work platform and a pair of similar upper trusses abovethe platform and having a plurality of guard rail posts supporting aplurality of horizontal safety guard rails for protecting operators fromfalling from the platform. With this type of arrangement wherein theplatform is installed at the upper end of the lower trusses and theassociated guard rails are mounted to the trusses of the nextscaffolding level, it is not possible to install the guard rails of agiven level before accessing the platform of this level. There is thus arisk that the operator falls from the platform while erecting thescaffold. Consequently, regulations requiring that the operator bestrapped to the structure while building up the scaffold have beenimposed. Despite the regulations and the relatively high risk ofaccidents, the operators often do not strap themselves to thescaffolding structure.

[0005] There is thus a need for a new scaffolding system wherein thesafety guard rails of a scaffold which is being erected can be installedfrom the already erected underlying scaffolding level so that theoperator stepping on the next floor level will be already protected fromfalling by the pre-installed guard rails.

SUMMARY OF THE INVENTION

[0006] It is therefore an aim of the present invention to provide a newscaffolding system in which the guard rails of a next scaffolding levelto be erected can be installed from an underlying level.

[0007] It is also an aim of the present invention to provide a method bywhich a scaffold can be erected in a safe and simple way.

[0008] Therefore, in accordance with the present invention, there isprovided a scaffold of the type used in the construction of buildings,comprising a first work platform supported at opposed ends thereof by afirst pair of trusses, each of said trusses having a pair of uprightshaving top and bottom ends, said uprights being interconnected by a workplatform support extending horizontally between said uprights at alocation intermediate the top and bottom ends thereof, and connectionson said uprights above said work platform support for pivotallyconnecting at least one guard rail to said first pair of trusses abovesaid first work platform.

[0009] In accordance with a still further general aspect of the presentinvention, there is provided a multi-level construction scaffoldingcomprising at least first and second levels, each of said first andsecond levels comprising a work platform supported at opposed endsthereof by a pair of generally H-shaped trusses interconnected by a pairof guard rails extending above said work platform, each truss having apair of uprights interconnected to each other at a location intermediatetheir top and bottom ends by a horizontal platform support member uponwhich the platform rests, wherein the guard rails and the work platformof a same level are supported by the same pair of H-shaped trusses.

[0010] In accordance with a still further general aspect of the presentinvention, there is provided a method of erecting a multi-levelscaffolding structure, comprising the steps of: erecting a firstscaffolding level comprising first and second end frames interconnectedby bracing, mounting a third end frame on top of said first end frame,pivotally connecting a first end of a guard rail to said third endframe, pivotally connecting a second end of said guard rail to a fourthend frame, lifting said fourth end frame on top of said second endframe, thereby causing said guard rail to pivot upwardly from aninclined position to a substantially horizontal position between saidthird and fourth end frames, and mounting a work platform to said thirdand fourth end frames below the already installed guard rail of thesecond scaffolding level.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Having thus generally described the nature of the invention,reference will now be made to the accompanying drawings, showing by wayof illustration a preferred embodiment thereof, and in which:

[0012] FIGS. 1 to 7 are perspective views illustrating the various stepsthat have to be followed for erecting a scaffolding structure inaccordance with a preferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] FIGS. 1 to 7 illustrate a scaffolding system 10 whereby anoperator can install the guard rails of a next level before accessingit, thereby greatly improving the operator's safety while assembling thescaffolding. As will be seen hereinafter, the scaffold guard rails arepivotally connected at a first end thereof to an already installed trussand at a second end thereof to a not yet installed second truss so thatwhen the second truss is lifted in position onto an already installedtruss of the underlying scaffolding level, the guards pivot to ahorizontal position above the floor of the scaffold level that is beingerected.

[0014] More particularly FIG. 7 illustrates a multi-level scaffold 10comprising first and second scaffold levels 12 and 14 adapted to betemporarily mounted alongside of a building's wall. The levels 12 and 14are provided with respective vertical frames or H-shaped trusses 16/18and 20/22. Each H-shaped truss 16, 18, 20 and 22 includes a pair ofuprights 24 and 26 interconnected by a work platform support 28extending horizontally between the uprights 24 and 26. As opposed toconventional inverted U-shaped trusses wherein the work platform supportis provided at the very upper end of the uprights 24 and 26, the workplatform support 28 is located approximately midway between the top andbottom ends of the uprights 24 and 26. According to the illustratedembodiment, the platform support 28 is in fact located in the lower haftportion of the uprights 24 and 26. As will be seen hereinafter, loweringthe position of the work platform support 28 advantageously allowsinstalling the safety guard rails of a next level to be erected from thealready installed underlying scaffold level.

[0015] Each H-shaped truss 16, 18, 20 and 22 further includes a pair ofdiagonal reinforcing members 30 extending from the lower end portion ofopposed uprights 24 and 26 to the work platform support 28. Thereinforcing structure further comprises a horizontal member 32 extendingbetween the diagonal members 30 just below the work platform support 28.Horizontal struts 34 are also provided between the diagonal members 30and the associated upright 24/26.

[0016] The uprights 24 and 26 and the work platform support 28 arepreferably made of steel tubing whereas the diagonal members 30, thehorizontal member 32 and struts 34 are preferably made of extrudedsteel. All these members are fixedly secured together as by welding.

[0017] The top ends of uprights 24 and 26 are provided with reduceddiameter segments 36 that are sized to fit into the lower tubularportions of the uprights of the next truss, thereby allowing the trussesto be stacked into towers. To secure the trusses together, the reduceddiameter segments 36 and the lower tubular portions of the uprights areprovided with transversal registering holes (not shown) for receiving alock pin (not shown).

[0018] First and second level platforms 38 and 40 are respectivelysupported at opposed ends thereof by the platform supports 28 of thefirst level trusses 16 and 18 and the platform supports 28 of the secondlevel trusses 20 and 22. A ladder 42 is mounted between the firstplatform 38 and the second platform 40 for allowing an operator to climbto the second platform 40 from the first platform 38. The ladder 42 ishooked at its upper end to one of the platform support 28 on the secondlevel 14. A trap 44 is provided in the second platform 40 adjacent theupper end of the ladder 42 for allowing the operator to have access tothe second platform 40.

[0019] Top and intermediate vertically spaced-apart gravity locks 46 and48 are provided on the upper haft portion of each upright 24 and 26 toprovide for the installation of pairs of guard rails 52 between thefirst level trusses 16/18 as well as between the trusses 20/22 of thesecond level. Each gravity lock 46/48 comprises a pivot pin 50projecting horizontally from an upright towards the other upright of thesame truss.

[0020] Each guard rail 52 is provided in the form of a bar havingopposed flattened end portions, each of which defines a hole forallowing the guard rail 52 to be pivotally engaged onto the pivot pins50.

[0021] A bottom gravity lock 54 is provided on each upright 24/26 justbelow the platform support 28 for releasable engagement with crossbraces 56 extending between the trusses of a same level. Each crossbrace 56 is releasably connected at a first end thereof to the bottomgravity lock 54 of a given upright and at a second end thereof to thetop gravity lock 46 of the opposed facing uprights. Accordingly, the topgravity locks 46 not only act as the pivot points for the top guardrails 52 but also act as the top anchoring points for the cross braces56.

[0022] It is understood that when the scaffold is erected along abuilding wall, guard rails 52 does not have to be installed on both thefront and the rear sides of the scaffold 10. Indeed, as illustrated inFIGS. 1 to 7, they can be installed only on the front side of thescaffold.

[0023] Referring now to FIGS. 1 to 7, the procedures for erecting thescaffold 10 will now be described in greater details.

[0024] As shown in FIG. 1, the first scaffold level 12 is first erectedby first appropriately positioning on the ground a number of adjustablejacks 60. A first truss 16 is then installed in position on a first pairof jacks 60. Then, a first pair of cross braces 56 is connected at oneend thereof to the already installed truss 16, one brace being connectedto the top gravity lock 46 while the other is connected to the bottomgravity lock 54 of the front upright 26 of the already installed truss16. Thereafter, a second truss 18 is installed on a second pair of jacks60′ and the second opposed ends of the cross braces 56 are connected tothe bottom and top gravity locks 54 and 46 of the front upright 26 ofthe second truss 18 so as to define a X at the front side of the firstlevel of the scaffold 10. After having installed the cross braces 56,the first platform 38 can be placed onto the platform supports 28 of thealready installed trusses 16 and 18. Once the platform 38 has beenproperly leveled through the used of the jacks 60 and 60′, thehorizontal guard rails 52 are connected at opposed ends thereof to thetop and intermediate gravity locks 46 and 48 of the trusses 16 and 18.As shown in FIG. 1, further trusses and work platform can be added inseries to the first scaffolding level in order to provide the desiredlength of work platform along the building wall.

[0025] Once the first level 12 has been erected as describedhereinbefore, the first truss 20 of the second level 14 is placed inposition on the already installed first truss 16 of the first level 12.Then, while the operator is still on the work platform 38 of the firstlevel 12, two rail guards 52 are respectively pivotally engaged at oneend thereof with the pins 50 of the top and intermediate gravity locks46 and 48 provided on the front upright 26 of the first truss 20 of thesecond level.

[0026] As shown in FIG. 2, the two guard rails 52 are then respectivelypivotally connected to the top and bottom gravity locks 46 and 48 of thenot yet installed second truss 22 of the second level 14. Thereafter,the truss 22 is lifted in position on top of the already installedsecond truss 18 of the first level 12, thereby causing the second levelguard rails 52 to pivot from an inclined position to a horizontalposition above the work platform support 28 of the trusses 20 and 22, asshown in FIG. 3. This results in the guard rails 52 of the second level14 being installed from the first floor level 12 before the second levelplatform 38 be installed.

[0027] Once the guard rails 52 of the second level 14 have beeninstalled, a cross brace 56 is installed between the trusses 20 and 22as per the way described hereinbefore with respect to the cross braces56 of the first level 12. As shown in FIG. 4, further trusses, guardrails and braces can be mounted in series on the second level 14 byfollowing the same procedure.

[0028] As shown in FIG. 5, the next step consists of installing the workplatform 38 of the second level 14. The work platform 38 is hooked atopposed ends thereof to the platform supports 28 of the trusses 20 and22.

[0029] As shown in FIG. 6, the ladder 42 is subsequently hooked onto theplatform support 28 of the truss 22 for allowing the operator to accessthe second floor level of the scaffold. As can be appreciated from thedrawings and the above described procedure, the operator will already beprotected against falling from the scaffold when he/she will step on thesecond floor level platform 38.

[0030] Finally, as shown in FIG. 7, a second work platform can bemounted in series to the first platform 38 of the second level as perthe way described above.

[0031] The same steps must be followed for installing other levels.

[0032] The present invention is not limited to the illustratedembodiment and various changes can be made in the arrangement and designof the trusses, the guard rails and the cross braces without departingfrom the spirit of the present invention.

1 to
 7. (cancelled)
 8. A multi-level construction scaffolding comprisingat least first and second levels, each of said first and second levelscomprising a work platform supported at opposed ends thereof by a pairof generally H-shaped trusses interconnected by a pair of guard railsextending above said work platform, each truss having a pair of uprightsinterconnected to each other at a location intermediate their top andbottom ends by a horizontal platform support member upon which theplatform rests, wherein the guard rails and the work platform of a samelevel are supported by the same pair of H-shaped trusses.
 9. Amulti-level construction scaffolding as defined in claim 8, wherein thetwo guard rails are respectively engage with first and second verticallyspaced-apart pivot points provided on each truss at a distance abovesaid platform support member thereof.
 10. A multi-level constructionscaffolding as defined in claim 9, wherein at least one of said firstand second levels further includes a diagonal brace interconnecting thetrusses of a same level, and wherein said diagonal brace extends fromone of said first pivot points of a first one of said trusses, saiddiagonal brace being connected at an opposed end thereof to a thirdpivot point provided below the platform support member of a second oneof said trusses.
 11. A multilevel construction scaffolding as defined inclaim 8, wherein each of said trusses includes a pair of opposeddiagonal members extending upwardly from said uprights to said platformsupport member. 12 to
 14. (cancelled)